On Architecture

5. But if the loads of material for the work are still more colossal in size and weight, we shall not entrust them to a windlass, but set in an axle-tree, held by sockets as the windlass was, and carrying on its centre a large drum, which some term a wheel, but the Greeks call it a)mfi/esis or periqh/kion.

6. And the blocks in such machines are not arranged in the same, but in a different manner; for the rows of sheaves in them are doubled, both at the bottom and at the top. The traction rope is passed through a hole in the lower block, in such a way that the two ends of the rope are of equal length when it is stretched out, and both portions are held there at the lower block by a cord which is passed round them and lashed so that they cannot come out either to the right or the left. Then the ends of the rope are brought up into the block at the top from the outside, and passed down over its lower sheaves, and so return to the bottom, and are passed from the inside to the sheaves in the lowest block, and

7. Passing over these from the outside, they are then carried to the right and left of the drum on the axle-tree, and are tied there so as to stay fast. Then another rope is wound round the drum and carried to a capstan, and when that is turned, it turns the drum and the axle-tree, the ropes get taut as they wind round regularly, and thus they raise the loads smoothly and with no danger. But if a larger drum is placed either in the middle or at one side, without any capstan, men can tread in it and accomplish the work more expeditiously.

8. There is also another kind of machine, ingenious enough and easy to use with speed, but only experts can work with it. It consists of a single timber, which is set up and held in place by stays on four sides. Two cheeks are nailed on below the stays, a block is fastened by ropes above the cheeks, and a straight piece of wood about two feet long, six digits wide, and four digits thick, is put under the block. The blocks used have each three rows of sheaves side by side. Hence three traction ropes are fastened at the top of the machine. Then they are brought to the block at the bottom, and passed from the inside round the sheaves that are nearest the top of it. Then they are brought back to the upper block, and passed inwards from outside round the sheaves nearest the bottom.